When people eat a lot of salt, their kidneys use a specific part (the DCT) to reabsorb more sodium — so when you give them a diuretic like hydrochlorothiazide, it works way better at making them pee out salt.

When healthy young men eat a lot of salt, their kidneys use the part of the tubule that thiazide drugs target to reabsorb more sodium — so when you give them a thiazide, it works way better at making them pee out salt.

When healthy young men eat a lot of salt, their kidneys use the DCT part more to reabsorb sodium — even though the sodium pump in that part becomes less active — because more sodium is being filtered and pushed through.

When healthy young men eat a lot of salt, their kidneys use the DCT part more to reabsorb sodium — even though the sodium pump in that area is less active — because more sodium is being filtered, so the kidney works harder there.

When you eat little salt, your kidneys rely more on a specific channel (ENaC) to hold onto sodium — so blocking it with amiloride makes you pee out a lot more salt. When you eat a lot of salt, that channel isn’t as important, and another part of the kidney (DCT) handles most of the sodium.

When healthy young men eat very little salt, their kidneys rely more on a specific sodium pump (ENaC) in the final part of the kidney to hold onto sodium — and blocking that pump removes as much sodium as blocking the earlier pump.